// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef UI_GFX_SHADOW_VALUE_H_
#define UI_GFX_SHADOW_VALUE_H_

#include <string>
#include <vector>

#include "third_party/skia/include/core/SkColor.h"
#include "ui/gfx/geometry/vector2d.h"
#include "ui/gfx/gfx_export.h"

namespace gfx {

class Insets;

class ShadowValue;
typedef std::vector<ShadowValue> ShadowValues;

// ShadowValue encapsulates parameters needed to define a shadow, including the
// shadow's offset, blur amount and color.
class GFX_EXPORT ShadowValue {
public:
    ShadowValue();
    ShadowValue(const gfx::Vector2d& offset, double blur, SkColor color);
    ~ShadowValue();

    int x() const { return offset_.x(); }
    int y() const { return offset_.y(); }
    const gfx::Vector2d& offset() const { return offset_; }
    double blur() const { return blur_; }
    SkColor color() const { return color_; }

    ShadowValue Scale(float scale) const;

    std::string ToString() const;

    // Gets margin space needed for shadows. Note that values in returned Insets
    // are negative because shadow margins are outside a boundary.
    static Insets GetMargin(const ShadowValues& shadows);

private:
    gfx::Vector2d offset_;

    // Blur amount of the shadow in pixels. If underlying implementation supports
    // (e.g. Skia), it can have fraction part such as 0.5 pixel. The value
    // defines a range from full shadow color at the start point inside the
    // shadow to fully transparent at the end point outside it. The range is
    // perpendicular to and centered on the shadow edge. For example, a blur
    // amount of 4.0 means to have a blurry shadow edge of 4 pixels that
    // transitions from full shadow color to fully transparent and with 2 pixels
    // inside the shadow and 2 pixels goes beyond the edge.
    double blur_;

    SkColor color_;
};

} // namespace gfx

#endif // UI_GFX_SHADOW_VALUE_H_
